Palaeoenvironments of early hominins in temperate and Mediterranean Eurasia: new palaeobotanical data from Palaeolithic key-sites and synchronous natural sequences     

Erwan Messager  Vincent Lebreton  Laurent Marquer  Elda Russo-Ermolli  Ronan Orain  Josette Renault-Miskovsky  David Lordkipanidze  Jackie Despriée  Carlo Peretto  Marta Arzarello 《Quaternary Science Reviews》2011,30(11-12):1439-1447

The present study focuses on new palaeobotanical data (pollen, phytoliths and fruits) from three of the oldest Early Palaeolithic sites in Eurasia (Dmanisi in Georgia, Ca’ Belvedere di Monte Poggiolo in Italy and Pont-de-Lavaud in France). The main aim is to examine the ecological factors associated with the first human dispersals out of Africa into Eurasia. The palaeoecological data are discussed with regards to chronology and geographical location of the settlements. The vegetation pattern of each site consists of temperate Eurasian and Mediterranean taxa, subtropical trees being more or less recorded depending on climatic and geographic features. The new palaeobotanical data show that different vegetation structures occurred between the first human dispersal in Caucasus and the later dispersals in western Eurasia. However, in all cases hominins seemed to be adapted to temperate ecosystems. In Caucasus, human occupation took place at 1.7 Ma in a forest-steppe environment, while at ca 1 Ma human populations occupied various settings such as open landscapes or dense forests. These data suggest that during the Early Pleistocene, human populations evolved and dispersed in western Eurasia, gradually increasing their degree of adaptation to diversified environments.  相似文献   

Airborne lidar measurements of aerosol spatial distribution and optical properties over the Atlantic Ocean during a European pollution outbreak of ACE‐2     

Cyrille Flamant  Jacques Pelon  Patrick Chazette  Vincent Trouillet  Patricia K. Quinn  Robert Frouin  Didier Bruneau  Jean François Leon  Timothy S. Bates  James Johnson  John Livingston 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):662-677

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Laboratory experiments of slab break‐off and slab dip reversal: insight into the Alpine Oligocene reorganization     

Vincent Regard  Claudio Faccenna  Olivier Bellier  Joseph Martinod 《地学学报》2008,20(4):267-273

We present laboratory experiments to study the consequence of the rupture of a subducting slab on the deep geometry of the subduction zone. In our experiments, slab break‐off occurs after the entrance of buoyant material at trench causing a slowing down of the subduction and producing an increase of the shortening rate and a transient episode of subduction dip reversal. We discuss the potential application of these processes to the recent collisional evolution of the Alps proposing that the rupture of the slab produced a reorganization of the belt with a transition from one sided to a doubly vergent orogen.  相似文献   

The baryon fraction of ΛCDM haloes     

Robert A. Crain  Vincent R. Eke  Carlos S. Frenk  Adrian Jenkins  Ian G. McCarthy  Julio F. Navarro  Frazer R. Pearce 《Monthly notices of the Royal Astronomical Society》2007,377(1):41-49

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The probability distribution function of the Lyman α transmitted flux from a sample of Sloan Digital Sky Survey quasars     

Vincent Desjacques  Adi Nusser  Ravi K. Sheth 《Monthly notices of the Royal Astronomical Society》2007,374(1):206-219

We present a measurement of the probability distribution function (PDF) of the transmitted flux in the Lyman α (Lyα) forest from a sample of 3492 quasars included in the Sloan Digital Sky Survey data release 3 (SDSS DR3). Our intention is to investigate the sensitivity of the Lyα flux PDF as measured from low-resolution and low signal-to-noise ratio data to a number of systematic errors such as uncertainties in the mean flux, continuum and noise estimate. The quasar continuum is described by the superposition of a power law and emission lines. We perform a power-law continuum fitting on a spectrum-by-spectrum basis, and obtain an average continuum slope of  α_ν= 0.59 ± 0.36  in the redshift range  2.5 < z < 3.5  . We take into account that the variation in the continuum indices increases the mean flux by 3 and 7 per cent at   z = 3  and 2.4, respectively, as compared to the values inferred with a single (mean) continuum slope. We compare our measurements to the PDF obtained with mock lognormal spectra, whose statistical properties have been constrained to match the observed Lyα flux PDF and power spectrum of high-resolution data. Using our power-law continuum fitting and the SDSS pipeline noise estimate yields a poor agreement between the observed and mock PDFs. Allowing for a break in the continuum slope and, more importantly, for residual scatter in the continuum level substantially improves the agreement. A decrease of ∼10–15 per cent in the mean quasar continuum with a typical rms variance at the 20 per cent level can account for the data, provided that the noise excess correction is no larger than ≲10 per cent.  相似文献   

A pollen–climate calibration from western Patagonia for palaeoclimatic reconstructions     

Vincent Montade  Odile Peyron  Charly Favier  Jean Pierre Francois  Simon G. Haberle 《第四纪科学杂志》2019,34(1):76-86

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In situ cosmogenic exposure ages from the Isle of Skye,northwest Scotland: implications for the timing of deglaciation and readvance from 15 to 11 ka     

David Small  Vincent Rinterknecht  William Austin  Derek Fabel  Maria Miguens‐Rodriguez  Sheng xu 《第四纪科学杂志》2012,27(2):150-158

We present 10 in situ cosmogenic exposure ages from two moraines on the Isle of Skye. The Strollamus medial moraine was deposited during deglaciation of the Devensian ice sheet and yields a mean exposure age from five samples of 14.3 ± 0.9 ka. The moraine age indicates that a significant ice mass existed on Skye at the time of a regional readvance recorded in Wester Ross, northwest Scotland. Taken at face value the ages suggest that deglaciation did not occur until well into Greenland Interstade 1. The Slapin moraine represents the local limit of the Loch Lomond Readvance (LLR) and yields a mean exposure age from five samples of 11.5 ± 0.7 ka, which is consistent with deposition relating to the LLR. These ages suggest that the maximum extent may have been reached late in the stadial and that some glaciers may have remained active until after the climatic amelioration that marks its end. This scenario is considered unlikely given the nature of the climate during this period, which leads us to call for a locally calibrated production rate. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Taxonomic addition to the early diverged parasitic wasps (Hymenoptera: Orussoidea) from the mid-Cretaceous Burmese amber     

Corentin Jouault  Vincent Perrichot  André Nel 《Proceedings of the Geologists' Association. Geologists' Association》2021,132(3):324-331

A new genus and species of orussoid wasps, Cretorussus vilhelmseni gen. et sp. nov., is described based on new material from the mid-Cretaceous Burmese amber. Its wing venation and body characters lead us to emend the diagnosis of the family Burmorussidae. Cretorussus vilhelmseni gen. et sp. nov. is considered to be a specialized parasitic wasp of wood-living hosts because of the orussid-like ocellar crown, antennae attached well above clypeus, and antennal grooves absent. Interestingly, the third tarsomere carries a prominent lanceolate lobe, serving as part of the host detection. We propose a summary of the orussoid fossil diversity. Lastly, we discuss the implications of several characters of Burmorussidae that are involved in host detection.  相似文献   

Geomorphology of a modern carbonate slope system and associated sedimentary processes: Example of the giant Great Abaco Canyon,Bahamas     

Audrey Recouvreur  Natacha Fabregas  Thierry Mulder  Vincent Hanquiez  Kelly Fauquembergue  Elsa Tournadour  Herv Gillet  Jean Borgomano  Emmanuelle Poli  Jean‐Baptiste Kucharski  Stanislas Wilk 《Sedimentology》2021,68(1):266-293

The large acoustic data set acquired during the Carambar cruises is composed of high resolution bathymetry, backscatter data and very‐high resolution seismic lines which allow for an overview of the morphology and sediment transfer processes from the shallow upper slope to the abyssal plain of a modern carbonate system: the north‐eastern slope of the Little Bahama Bank. Surficial distribution of the acoustic facies and echofacies reflects a wide variety of sedimentary processes along and across the slope. The western sector of the Little Bahama Bank is dominated by depositional processes whereas its eastern sector, which is incised in the lower slope by giant canyons, is affected by erosion and bypass processes. Datasets suggest that currents play an important role both in along‐slope sedimentary processes and in the abyssal plain. The Antilles Current appears to affect a large part of the middle and lower slopes. The absence of sizeable present‐day channel/levée complexes or lobes at the mouth of the canyon – revealed by the bathymetric map – indicates that the southward flowing Deep Western Boundary Current influences modern abyssal sediment deposition. Based on depositional processes and indicators of canyon maturity observed in facies distribution, the current study proposes that differential subsidence affects the eastern versus western part of the bank. The morphology of the Great Abaco Canyon and Little Abaco Canyon, which extend parallel to the platform, and the Little Bahama Bank slope appears to be related to the Great Abaco Fracture Zone.  相似文献   

Benthic status of near-shore fishing grounds in the central Philippines and associated seahorse densities     

Marcus JE  Samoilys MA  Meeuwig JJ  Villongco ZA  Vincent AC 《Marine pollution bulletin》2007,54(9):1483-1494

Benthic status of 28 near-shore, artisanal, coral reef fishing grounds in the central Philippines was assessed (2000-2002) together with surveys of the seahorse, Hippocampus comes. Our measures of benthic quality and seahorse densities reveal some of the most degraded coral reefs in the world. Abiotic structure dominated the fishing grounds: 69% of the benthos comprised rubble (32%), sand/silt (28%) and dead coral (9%). Predominant biotic structure included live coral (12%) and Sargassum (11%). Rubble cover increased with increasing distance from municipal enforcement centers and coincided with substantial blast fishing in this region of the Philippines. Over 2 years, we measured a significant decrease in benthic 'heterogeneity' and a 16% increase in rubble cover. Poor benthic quality was concomitant with extremely low seahorse densities (524 fish per km(2)). Spatial management, such as marine reserves, may help to minimize habitat damage and to rebuild depleted populations of seahorses and other reef fauna.  相似文献